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| author | Thomas Gleixner <tglx@linutronix.de> | 2019-08-21 22:09:07 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-08-28 12:50:35 +0300 |
| commit | 11b8462f7e1d25f639c88949a2746a9c2667a766 (patch) | |
| tree | 5d811cd589e5ac6187a91f6773c8d4819dac5d0e /include/linux/sched | |
| parent | 3a245c0f110e2bfcf7f2cd2248a29005c78999e3 (diff) | |
| download | linux-11b8462f7e1d25f639c88949a2746a9c2667a766.tar.xz | |
posix-cpu-timers: Provide array based access to expiry cache
Using struct task_cputime for the expiry cache is a pretty odd choice and
comes with magic defines to rename the fields for usage in the expiry
cache.
struct task_cputime is basically a u64 array with 3 members, but it has
distinct members.
The expiry cache content is different than the content of task_cputime
because
expiry[PROF] = task_cputime.stime + task_cputime.utime
expiry[VIRT] = task_cputime.utime
expiry[SCHED] = task_cputime.sum_exec_runtime
So there is no direct mapping between task_cputime and the expiry cache and
the #define based remapping is just a horrible hack.
Having the expiry cache array based allows further simplification of the
expiry code.
To avoid an all in one cleanup which is hard to review add a temporary
anonymous union into struct task_cputime which allows array based access to
it. That requires to reorder the members. Add a build time sanity check to
validate that the members are at the same place.
The union and the build time checks will be removed after conversion.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192921.105793824@linutronix.de
Diffstat (limited to 'include/linux/sched')
| -rw-r--r-- | include/linux/sched/types.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/sched/types.h b/include/linux/sched/types.h index 2c5c28ddd9b2..3c3e049224ae 100644 --- a/include/linux/sched/types.h +++ b/include/linux/sched/types.h @@ -6,8 +6,8 @@ /** * struct task_cputime - collected CPU time counts - * @utime: time spent in user mode, in nanoseconds * @stime: time spent in kernel mode, in nanoseconds + * @utime: time spent in user mode, in nanoseconds * @sum_exec_runtime: total time spent on the CPU, in nanoseconds * * This structure groups together three kinds of CPU time that are tracked for @@ -15,8 +15,8 @@ * these counts together and treat all three of them in parallel. */ struct task_cputime { - u64 utime; u64 stime; + u64 utime; unsigned long long sum_exec_runtime; }; |